private void DuplicateIfSharedAtIndex(Triangle<Vertex> triangle, Vertex toDuplicate)
{
int index = triangle.VertexIndex(toDuplicate);
if (index >= 0)
{
Vertex newVertex = new Vertex { Id = vertexIndex++, Position3D = new Vector3(toDuplicate.Position3D.x, toDuplicate.Position3D.y, toDuplicate.Position3D.z) };
triangle.Vertices[index] = newVertex;
Vertices.Add(newVertex);
}
}
